Protective clothing fabric

ABSTRACT

A flame-resistant and toxic chemical-agent protective clothing fabric woven of aromatic polyamide yarns and carbon yarns having at least 12 mg of carbon yarn per square centimeter of fabric, said carbon yarns having a carbon tetrachloride vapor sorption capacity of at least 15 percent by weight.

United States Patent 1 Henry'et al.

[111 3,744,534 1 July 10,1973

[ PROTECTIVE CLOTHING FABRIC [73] Assignee: The United States of Americaas represented by the Secretary of the Army, Washington, DC.

[22] Filed: Apr. 12, 1972 21 Appl. No.2 243,436

[52] U.S. Cl 139/426, 2/2, 2/81, 57/140 B, 423/447 [51] Int. Cl D03d15/00 [58] Field of Search 139/420 R, 426 R; 2/2, 81; 8/1 16 R, l16.2;423/447; 57/140, 140 B, 144; 66/202 [56] References Cited Y UNITEDSTATES PATENTS 3,235,323 2/1966 Peters 8/1 16.2 3,484,183 12/1969Dickson et al. 8/116 R 3,556,712 l/l97l Yoneshige et a1. 423/4473,527,564 9/1970 Moore et al. 423/447 3,607,672 9/1971 Schmitt. 8/116 R3,572,397 3/197l Austin 139/426 R 2,252,554 8/1941 Carothers 260/783,586,596 6/1971 Ainsworth et al. 2/2

FOREIGN PATENTS 'OR APPLICATIONS 1,162,110 8/1969 Great Britain ..2/81

OTHER PUBLICATIONS Nomex: Promising Raw Material for Industrial Knits,Knitted Outerwear Times, Vol. 39 No. 28 July 6, 1970 pages 28, 29, 58and 59.

Properties of Nomex, High Temperature Resistant Nylon Fiber, Du PontTechnical Information Fibers, Nomex Nylon Bulletin N-236 Oct. 1969.

Graphite Now Produced inFlexible Textile Form-Applications Limitless,Mechanical Engineering, June 1959 page 121.

France 139/426 R Primary Examiner-James Kee Chi Attorney Harry M.Saragovitz, Edward J. Kelly et al.

57 ABSTRACT A flame-resistant and toxic chemical-agent protectiveclothing fabric woven of aromatic polyamide yarns and carbon yarnshaving at least 12 mg of carbon yarn per square centimeter of fabric,said carbon yarns having a carbon tetrachloride vapor sorption capacityof at least 15 percent by weight.

10 Claims, No Drawings PROTECTIVE CLOTHING FABRIC The inventiondescribed herein may be manufactured, used and licensed by or for theGovernment for governmental purposes without the payment to us of anyroyalty thereon.

BACKGROUND OF THE INVENTION This invention is concerned with woventextile fabrics to be used in the fabrication of protective clothing toshield the wearer thereof from certain toxic organic gases or vapors.

Individuals exposed to toxic gases and liquids have, heretofore,protected their bodies by donning certain protective garments which areimpermeable" to both gases and liquids. Clothing that is completelyimpermeable to gases can be worn for only short periods of time withoutdiscomfort or fatigue due to the retention of body heat and moisturewithin the air space defined by the garment. The buildup of body heatand moisture within the garment results, at a minimum, in discomfort andunder certain circumstances can result in excessive and debilitatingthermal stress to the individual. Consequently, impermeable garments mayonly be worn for extremely brief periods of time, a serious drawback, ormust be combined with auxiliary ventilating equipment which limitsmobility and creates additional logistical and physical burdens. Otherforms of protection employed include outer-garments of foam impregnatedwith activated carbon and clothing liners of woven fabric impregnatedwith chloramide materials and chlorinated paraffin. These forms ofprotection have proven' to be unsatisfactory because of thephysiological stress that they impose on the wearer by virtue of theirbulk, weight or insulative properties. Considerable research, however,has been directed toward the development of to yarns comprised of fibershaving a carbon content of from 50 up to 99+ percent. For purposes ofthis invention, it is required that the carbon yarns have a carbontetrachloride sorption capacity of at least percent by weight. Theextent of vapor sorptioncapacity or degree of activation of the carbonmaterial has a finite upper limit which is governed in part by thenature of the carbon precusor as well as the activation conditions orprocedures, which are well known to those skilled in the art. Carbonyarns having any significant vapor sorption capacity are known to haveextremely poor tensile or breaking strength properties (typically lessthan 1 gm denier) as well as poor abrasion resistance and poor flexingproperties, all of which make such yarns unsuitable for use in clothingapplications. Descriptions of suitable carbon yarns and methods ofmanufacture are found in US. Pat. No. 3,235,323 .to E. N. Peters; US.Pat. No. 3,484,183 to A. D. Dickson and E. N. Pe-

ters and U.S. Pat. No. 3,556,712 to Yoneshige, et al. 2

Examples of commercially available yarns meeting the requirements ofthis invention are Pluton B1 and Pluton PX563, both products of 3MCompany.

Aromatic polyamides are polymers which exhibit an unusually high degreeof stability when exposed to elevated temperatures. High melting pointsor lack of a melt point before thermal degradation are characteristicsof the aromatic polyamides. These polymers are highly resistant toflaming and are extinguished once an air-permeable material that can beworn with comfort and at the same time detoxify or attenuate the effects of toxic gases or liquids in the environment. Until the presentinvention, there has been no practical permeable sorptive woven clothingfabric that could be .worn with comfort and could actually protect thewearer from all toxic gas agents present in the environment.

SUMMARY OF THE INVENTION This invention relates to woven textile fabricsuseful in fabricating permeable, flame-resistant, toxic chemical-agentprotective clothing. The fabric is woven from aromatic polyamide yarnsand carbon yarns having a carbon tetrachloride vapor sorption capacityof at least 15 percent by weight. The carbonyarns are uniformlydistributed throughout the fabric in an amount sufficient to provide atleast 12 milligrams of carbon yarn for each square centimeter of fabric.

DESCRIPTION OF THE PREFERRED EMBODIMENTS the flame source is removed.Typically, these polymers are formed by copolymerizing aromatic diamineswith dicarboxylic acids, e.g., metaphenylenediamine with isophthalicacid. Nomex, a product of E. I. DuPont deNemours and Co., is but oneexample of a commercially available aromatic polyamide yar'n.

The woven fabrics of this invention have aromatic polyamide yarns in thefilling and warp directions with carbon yarns also woven in either orboth directions. The strength of the fabric in the warp and filldirections is at least lbs perinch as measured by Method 5102 of theFederal Test Method Standard l9l. To be effective, the carbon yarn mustbe substantially uniformly distributed through the woven fabric, i.e., acomponent of either or both the filling and warp yarns. It is essential,for the purposes of this invention, that there be at least 12 mg of theabove defined carbon yarn in each square centimeter of woven fabric. Thefabric should also be woven so as to have an air permeability of atleast 50 cubic feet/minute/square foot of fabric.

Clothing or garments constructed with the fabric of this inventionprovide a high degree of protection against the passage of toxic,organic gases. Toxic, or-

ganic chemical gases, or liquids which readily volatize to produce suchgases, are selectively adsorbed by the carbon yarns of the fabric andthus prevented from passing through the fabric to the body of thewearer. For example, vesicant military gases, such as mustard orlewisite, which are capable of producing painful and incapacitatingblisters when allowed to contact the skin, can be efiectively held backby preferential adsorption in the carbon yarns of the clothing fabric ofthis invention. The expression toxic chemical agentprotective fabric,refers to fabric which can absorb relatively large quantities of toxicorganic gases. A satisfactory sorptivity in this context is 95.5micrograms of mustard sorbed out of a total of micrograms. Whileeffective in retaining or absorbing toxic chemical gases, the samegarment, by virtue of its high air-permeability (over 50 cubic feet perminute per square foot) and reduced thickness may be worn with reducedphysical stress being placed on the wearer. In addition to the foregoingdesirable properties, this fabric exhibits a high degree-of flameresistance due to the unique combination of properties of the 2 yarncomponents. Flame resistance refers to the ability of the fabric to selfextinguish when the flame source is withdrawn.

EXAMPLE 1 A fabric according to the invention is constructed by wavingPluton PX 563 yarn with Nomex yarn. The Pluton carbon yarn has a surfacearea of 240 square meters per gram, a strength of 2.8 lbs per yarn,denier (g per 9,000 meters) of 1152, and a twist having 2.8 turns perinch. The Nomex yarns are 3 ply (200 denier) and 2 ply 200 denier). Aplain weave fabric was constructed having the 3 ply Nomex in the warpand the 2 ply Nomex and the carbon yarn woven together in the filldirection. The resulting fabric had a yarn count of 34 ends per inch and34 picks per inch, a thickness of 26-27 mils, a weightof 10.5 ounces persquare yarn, air-permeability (Federal Test Method Standard 191, Method5450) of 82 cubic feet per minute per square foot and strength (FederalTest Method Standard 191, Method 5102) in the warp of 150 lbs per inchof sample and in the fill of 92 lbs per inch of sample. The flameresistance of the fabric, as determined by the Federal Test MethodStandard 191, Method 5902, was as follows:

Warp, after flame, seconds Warp, after glow, seconds 7 Warp, charlength, inches 0 Fill, after flame, seconds 0 Fill, after glow, seconds4 Fill, char length, inches 1.4

ter resulted in less than 5 micrograms penetration per centimeter ofsquare fabric. These results indicate a high levelof protection againstmustard vapor.

We claim:

l. A woven, flame-resistant, toxic chemical agentprotective clothingfabric comprising flame resistant aromatic polyamide yarns interwovenwith carbon yarns, said carbon yarns having a carbon tetrachloride vaporsorption capacity of at least 15 percent by weight, and the minimumweight of said carbon yarn in said fabric being at least 12 milligramsper square centimeter.

2. A clothing fabric, according to claim 1, wherein said carbon yarnsare uniformly distributed throughout the fabric.

3. A clothing fabric, according to claim 2, wherein said polyamide yarnsof said fabric are woven in the fill and in the warp directions.

4. A clothing fabric, according to claim 3, wherein the air permeabilityof said fabric is at least 50 cubic feet per minute per square foot offabric.

5. A clothing fabric, according to claim 4, wherein the strength of saidfabric in the warp and fill directions have at least 90 lbs per inch.

6. A clothing fabric, according to claim 5, wherein the warp of saidfabric consists of a 3 ply (200 denier) aromatic polyamide yarn and thefill is a combination of a 2 ply (200 denier) aromatic polyamide yarnand the carbon yarn.

7. A clothing fabric, according to claim 6, wherein the weave is a plainweave.

8. A method of protecting a wearer from a toxic chemical gas agent whichcomprises enclosing said wearer in a clothing garment constructed of afabric comprising flame resistant aromatic polyamide yarns interwovenwith carbon yarns, said carbon yarns having a carbon tetrachloride vaporsorption capacity of at least 15 percent by weight, and the minimumweight of said carbon yarn in said fabric being at least 12 milligramsper square centimeter.

9. A method according to claim 8 wherein said carbon yarns are wovenuniformly throughout said fabric.

10. A method according to claim 9 wherein said aromatic polyamide yarnsare woven in the fill and warp directions.

2. A clothing fabric, according to claim 1, wherein said carbon yarnsare uniformly distributed throughout the fabric.
 3. A clothing fabric,according to claim 2, wherein said polyamide yarns of said fabric arewoven in the fill and in the warp directions.
 4. A clothing fabric,according to claim 3, wherein the air permeability of said fabric is atleast 50 cubic feet per minute per square foot of fabric.
 5. A clothingfabric, according to claim 4, wherein the strength of said fabric in thewarp and fill directions have at least 90 lbs per inch.
 6. A clothingfabric, according to claim 5, wherein the warp of said fabric consistsof a 3 ply (200 denier) aromatic polyamide yarn and the fill is acombination of a 2 ply (200 denier) aromatic polyamide yarn and thecarbon yarn.
 7. A clothing fabric, according to claim 6, wherein theweave is a plain weave.
 8. A method of protecting a wearer from a toxicchemical gas agent which comprises enclosing said wearer in a clothinggarment constructed of a fabric comprising flame resistant aromaticpolyamide yarns interwoven with carbon yarns, said carbon yarns having acarbon tetrachloride vapor sorption capacity of at least 15 percent byweight, and the minimum weight of said carbon yarn in said fabric beingat least 12 milligrams per square centimeter.
 9. A method according toclaim 8 wherein said carbon yarns are woven uniformly throughout saidfabric.
 10. A method according to claim 9 wherein said aromaticpolyamide yarns are woven in the fill and warp directions.